Can you post the code for your renderer?  How many bytes total for 150 images 
at this lower resolution?  Can you pre-compute the total set of images?

Thanks,
-Alex
________________________________________
From: Gabriele Campi [[email protected]]
Sent: Monday, June 30, 2014 9:34 AM
To: [email protected]
Subject: Re: list of images: poor performances

Hi Alex,

I've created a 150x80 version of my images but performances are almost
the same (at least on Android)

Gabri


Il 30/06/14 17:19, Alex Harui ha scritto:
> Hi Gabriele,
>
> You say your renderer is 150x80, yet the source images are 400x400 and up to 
> 100KB.
>
> Image loading is asynchronous, but bitmap rendering is not.  If a 400x400 
> image has to be shrunk to 150x80, that will take a lot of CPU power.  It 
> would be better to have the images re-sampled before downloading.  There will 
> be less data and the bitmap renderer will not have to shrink images.  As a 
> test, chop a bunch of images to the right size and see if it performs better.
>
> -Alex
> ________________________________________
> From: Gabriele Campi [[email protected]]
> Sent: Monday, June 30, 2014 8:11 AM
> To: [email protected]
> Subject: Re: list of images: poor performances
>
> My custom ItemRenderer is 150x80
> I display 18 items at the same time
> Using an IconItemRenderer doesn't help
>
>
> *GABRIELE CAMPI*
> Graphical Department
>
>
> Il 30/06/14 17:09, Gabriele Campi ha scritto:
>> 150 images
>> Size 10 to 100 KB
>> 400x400 pixel
>>
>> On iPad retina is almost ok. On iPad2/Mini is slow. On Android (galaxy
>> tab 2) the list is unusable.
>> Every new row of the list seems to freeze the ui while images are loading.
>> I don't understand, Isn't the load process of the images asynchronous?
>>
>> Gabri
>>
>>
>>
>> Il 30/06/14 16:49, Alex Harui ha scritto:
>>> How many images are we talking about?  What pixel dimensions are the images 
>>> in the list?  What are some of the sizes in bytes of the images being 
>>> downloaded?
>>>
>>> -Alex
>>> ________________________________________
>>> From: Gabriele Campi [[email protected]]
>>> Sent: Monday, June 30, 2014 6:30 AM
>>> To: Javier Guerrero García; users
>>> Subject: Re: list of images: poor performances
>>>
>>> Nothing seems to work... performances are even worse with a timer or delay
>>> I cannot cache all the images because of memory consumption
>>>
>>> Il 28/06/14 10:44, Javier Guerrero García ha scritto:
>>>> Also adjust the opaqueBackground, don't set the image sources
>>>> inmediately but after a short timeout (so if you scroll down fast
>>>> skipping lets say 50 images you DON'T load 50 images before loading
>>>> the 51st), and use a contentCache loader with queueing
>>>> (http://corlan.org/2011/08/16/flex-mobile-development-caching-images-using-contentcache/)
>>>>
>>>>
>>>> P.S. you can use the ContentCache straight from MXML, not like the
>>>> sources in the link. Just declare it, set an ID and the rest of the
>>>> parameters, and set contentCache="{id}" in your itemRenderer.
>>>>
>>>>
>>>> On Sat, Jun 28, 2014 at 6:58 AM, Alex Harui <[email protected]
>>>> <mailto:[email protected]>> wrote:
>>>>
>>>>       Make sure you are using a bitmap cache and that the images are not
>>>>       being scaled down on the device.
>>>>       Sent via the PANTECH Discover, an AT&T 4G LTE smartphone.
>>>>
>>>>       Gabriele Campi <[email protected]
>>>>       <mailto:[email protected]>> wrote:
>>>>
>>>>
>>>>       Hi,
>>>>       in a mobile app I need to display a list of 200 images. On the list I
>>>>       use a tileLayout with virtualLayout=true and a custom itemRenderer
>>>>       that
>>>>       only contains a Spark Image. On the set value method of the
>>>>       itemrenderer
>>>>       I change the source of the image with the path to the new bitmap.
>>>>       It works, but performances are poor and the list doesn't scroll
>>>>       well. On
>>>>       iPad it's almost acceptable, but on Android I have to scroll row
>>>>       by row
>>>>       and wait until every image of the row is loaded.
>>>>       Any suggestions to improve the situation?
>>>>       Thanks
>>>>
>>>>       Gabriele
>>>>
>>>>
>

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